AMD's Mark Papermaster, senior vice president and chief technology officer of AMD, has said that they will be making a major change to its manufacturing process in 2013. AMD is planning on switching from its current SOI process to a 28nm Bulk CMOS process for the 2013 line of products. This, however, should not affect GPU manufacturing.
The current 7000 series "Southern Islands" GPUs currently makes use of TSMC's 28nm process. The upcoming "Sea Islands" GPUs will continue to make use of TSMC's 28nm process. The Sea Islands GPUs have already entered tape-out and should begin being manufactured in the end of 2012. The product should release first quarter of 2013.
Additionally, Papermaster pointed out that AMD is not opposed to working with other manufacturing houses as long as they benefit AMD in product launches. Papermaster furthermore commented that the HSA foundation was not directed at any specific competitor and ARM and AMD are only working together to combine ARM's TrustZone into AMD's APUs.